The DIY Instrument (formally the Lumiphone) takes about 1 hour to make, most of which is soldering. Once you have made your instrument: sensors detect the light emitted by the LEDs. You use your finger to interrupt the beams of light. The left beam controls the volume and the right beam controls the pitch.
Here’s an official demoing the build for the original Lumiphone:
Here’s an unofficial demo of a completed Lumiphone:
The DIY Instrument Kit is available now for £10.00.
via Palm Sounds